The jet of an aircraft turbojet constitutes a relatively significant source of noise, which it is necessary to reduce in particular during the takeoff and landing phases of the aircraft, in order to best limit the noise nuisances suffered by airport inhabitants.
In a known manner, the jet of a dual-flow turbojet is made up of a hot primary flow escaping from an annular space situated between a nozzle and a gas ejection cone, and by a cool secondary flow escaping from an annular space defined radially, toward the inside, by this same nozzle.
In order to reduce the jet noise, it has been proposed in the prior art to place chevrons on the downstream end of the nozzle, so as to allow better mixing of the primary and secondary flows, synonymous with reducing the jet noise. Such a configuration using chevrons is for example known from documents EP 1 580 419 and US 2006/053769.
In general, the implementation of chevrons is satisfactory in terms of observed noise reduction, but it is largely detrimental to the performance of the turbojet, due to the aerodynamic disturbance created on the primary, secondary and outside flows.
The harmful aerodynamic impact on the secondary flow is even more restrictive given that on current turbojets, the high rate of dilution means that this flow is supposed to deliver 80% or more of the thrust.
Moreover, chevrons are often extremely difficult to install, in particular due to a nozzle trailing edge with an extremely small thickness.